PDFs are a file format created by Adobe that creates a file that is readable on many platforms without requiring special software to read and is generally not easy to edit. These are good qualities for sending out a file that you want for someone to only read. For that reason, it is used in many professional capacities. While it is possible to make PDFs accessible, did you know many of them out there are not? This article seeks to give an overview on some of the major accessibility problems that are common in PDFs as well as resources that you can use to help present accessible documents to students.
Note: You will need Adobe Acrobat to make changes to pre-existing PDF documents. The University of Minnesota has a license for Adobe Acrobat Pro DC available for faculty and staff.
What Makes an Accessible PDF?
The AccessibleU page on Documents and PDFs has 4 qualifications for an accessible document. The document must be:
- Searchable: Readers can use a digital device to search for words in the document.
- Scannable: Readers can quickly scan a document to find out what it contains.
- Legible: Sighted readers can physically read the text.
- Readable: Readers can easily understand the messages in the document.
Readability in regards to having the content being comprehensible. This is a decision that is up to you as the instructor. For this tutorial we will focus on the more technological concerns for accessibility such as accommodating screen readers and also
Many PDFs out there are from scans of documents and books. While most people can read the images from these scans, the computer may not. This means that screen readers will not work on those PDF documents and also means that the text is not searchable.
OCR stands for Optical Character Recognition. In short it is technology that helps computers recognize text and turn it into text that is recognizable to computers. Adobe Acrobat has a built in OCR software that can be used to convert a PDF’s scan of an image to have text that is usable to computers. That said the text would need to be legible in such a way that it is using a common font that looks clean. Chances are if you can’t read it, the computer can’t. Even in many cases the OCR may not recognize or confuse certain characters and mistakes in the conversion are possible depending on the quality of the text and print.
Check out Adobe’s Tutorial on Scan & OCR to make your PDFs text searchable.
The ability to scan a document quickly has a lot to do with the style of formatting your documents. The use of headers to chunk up information can allow readers to access the information they need quickly as well as seeing a quick overview of the topics and themes of a piece. Having properly headered PDFs makes your document scannable. The various parts of a document including the various levels of headings (i.e., Heading 1, Heading 2, etc.), paragraphs, tables and images all have tags associated with them to identify their purpose in the structure of a document to a screen reader.
Typically if a document has been created as a PDF from Microsoft Word it will take the tag and create the tags for the document. If the document went through OCR, Adobe will try to tag text components appropriately but it might require looking through and making sure the tagging and ordering on each page is appropriate.
As discussed in our article about Images and Accessibility, images in PDFs need alt text to be accessible for screen readers. Alt text in PDFs is vital for accessibility, especially with screen readers. It provides textual descriptions for images, ensuring that individuals with visual impairments can understand the content. Without alt text, important details and context in images may be lost, hindering accessibility. By including concise and informative alt text, content creators contribute to a more inclusive digital environment, allowing everyone to access and comprehend the information in PDF documents.
PDF Mediation and Beyond
Generally Word Documents that you have formatted appropriately and saved as a PDF will be searchable, scannable and legible in its PDF form. Once you have made the PDF, it’s always good to run an accessibility check through Adobe Acrobat.
For pre-existing PDFs, mediating them is a lot more involved than with web pages and Word Documents. There is also the meta-data that needs to be applied to the document for the title as well as the document’s language, read ordering of tagged items, etc. Sometimes you may encounter PDFs that are password protected meaning that unless you know the password, you won’t be able to edit the PDF document to make it accessible. Generally we advise staying away from PDFs in favor of other formats like other web pages using HTML or Word Documents. But if you want to work at making your PDFs accessible, check out the resources below: